1. Field of the Invention
The present invention relates to a medicine for the treatment of tumor, which is useful in the therapy of various cancerous diseases.
2. Description of the Background
Antitumor agents which are used in the treatment of cancerous diseases are generally accompanied by severe adverse side effects, which impose restrictions on the amount of the agents to be dosed. As a result, a problem arises in that expected therapeutic effects cannot be obtained. When a same antitumor drug is repreatedly administered to a patient for a long time, another problem occurs: tumor cells acquire tolerance against the antitumor drug, hindering the expected therapeutic effect from being exhibited. In order to solve these problems, conventional regimens have employed a combined use of plural antitumor agents.
However, the above problems, i.e., restricted dosage, adverse side effects, and drug resistance which are involved in conventional antitumor drugs have not yet been fully solved by the reliance on a combined use of plural antitumor agents.
The inventors of the present invention have investigated the action of wide-range substances and the action exhibited when an antitumor drug is used in combination with another drug, and as a result, have found that 4-piperidino-piperidine or its physiologically acceptable salts can suppress propagation of tumor cells, dissolve resistance against other antitumor drugs, and, when used in combination with other antitumor drugs, can enhance the antitumor effect of such other antitumor drugs.